Neomycin inhibits catecholamine secretion by blocking nicotinic acetylcholine receptors in bovine adrenal chromaffin cells
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- Title
- Neomycin inhibits catecholamine secretion by blocking nicotinic acetylcholine receptors in bovine adrenal chromaffin cells
- Authors
- Kim, KT; Choi, SY; Park, TJ
- Date Issued
- 1999-01
- Publisher
- AMER SOC PHARMACOLOGY EXPERIMENTAL TH
- Abstract
- We investigated the effects of neomycin on nicotinic acetylcholine receptor-induced responses in bovine adrenal chromaffin cells. Neomycin inhibited the nicotinic agonist dimethylphenylpiperazinium iodide (DMPP)-induced norepinephrine secretion in a concentration-dependent manner. Neomycin had also an inhibitory effect on the DMPP-induced increase in cytosolic Ca++ concentration ([Ca++](i)). This effect was further confirmed by inhibition of the DMPP-induced fluorescence quenching of fura-2 upon Mn++ entry. Under the same conditions, however, neomycin did not change the bradykinin-induced [Ca++](i) increase, which follows the downstream signal of phospholipase C phospholipase C activation in this cell. The inhibitory effect of neomycin on the DMPP-induced [Ca++](i) increase was apparent when the neomycin treatment was performed simultaneously with DMPP, suggesting a direct action on the nicotinic receptor. The direct inhibitory action of neomycin on the nicotinic receptor was also evident when neomycin inhibited the DMPP-induced cytosolic Ca++ increase, which is not affected by nifedipine nor omega-conotoxin MVIIC, and the cytosolic Na+ increase, which is not affected by tetrodotoxin. In addition, we observed that neomycin inhibited the binding of nicotine to the acetylcholine receptor in a noncompetitive manner. The data suggest that neomycin inhibits the nicotinic acetylcholine receptor directly, which results in blockage of the nicotinic receptor-mediated signaling without involvement of phospholipase C.
- Keywords
- PROTEIN-KINASE-C; AMINOGLYCOSIDE ANTIBIOTICS; NEUROMUSCULAR-TRANSMISSION; BINDING; CALCIUM; CURRENTS; CHANNELS; RELEASE; MUSCLE; STREPTOMYCIN
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/20543
- ISSN
- 0022-3565
- Article Type
- Article
- Citation
- JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS, vol. 288, no. 1, page. 73 - 80, 1999-01
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